Various in-vehicle warning systems can alert a driver of a vehicle to potential hazards in the driving environment. For example, a collision-avoidance system can detect a potential hazard and warn a driver when a collision appears possible or likely. Such warnings may include, for example, forward-collision warnings, side-collision warnings, rear-end collision warnings, headway warnings, blind-spot warnings, lane-departure warnings, and others. Other driver-assistance systems can assist the driver in operating the vehicle safely by providing warnings about roadway conditions, traffic, visibility, and other adverse conditions.
Various prior-art warning systems use parameters such as the time required for drivers to recognize potential road hazards and to complete collision avoidance responses. The parameters, however, are typically estimates based on the “typical” performance of a population of drivers, and do not account for individual differences among drivers. In addition, prior warning systems do not account for variations in driving behavior in different driving contexts. For example, prior systems typically assume that driver response times for avoiding a given hazard will be the same, regardless of the driving context. This can result in providing a warning that is too early or too late to be effective. Furthermore, prior warning systems do not provide for customization of the modality of the warning. For example, one driver may be quicker to respond to an auditory warning, while another driver may be quicker to respond to a haptic warning, and the prior warning systems typically do not take such individual differences into account.